Burner with Diffuser Resistant to High Operating Temperatures

ABSTRACT

A burner suppliable with a mixture of air and fuel, comprising a diffuser on which holes are made for the passage and subsequent combustion of said mixture, said diffuser being divided into a plurality of diffuser elements adjacent to one another, said diffuser elements are fixable to a support and distribution element provided with first coupling elements for coupling with said diffuser elements and with openings for distributing said mixture to said diffuser elements.

The present invention relates to a burner with a diffuser resistant tohigh operating temperatures, in particular to a premix burner.

In the burners subject to high operating temperatures, such as forexample the premix burners, the high thermal stresses can easily causesdeformation and mechanical stresses on the diffuser of the burner, whichmay cause the diffuser to break. This drawback occurs with any form ofdiffuser of the burner, but has been shown to be particularly serious inburners with flat diffusers. In order to remedy the above drawback, ithas been proposed to use special materials for making the diffuser ofthe burner, for example a metal mesh or a ceramic material. However,this results in a significant increase in the cost of the burner in theevent of use of the metal mesh and significant fragility of the diffuserin the event of use of a ceramic material.

It has also been proposed to divide the diffuser of the burner to reducemechanical stresses arising from temperature variations during burneroperation. Burners of this type are known from patent applicationsM02003A000180 and M02004A000031, in the name of the same applicant.

In these patent applications burners are disclosed wherein the diffuserof the burner is divided into a plurality of diffuser elements that areadjacent to one another, that are free to expand in at least onedirection.

The burners disclosed in the aforementioned patent applicationssatisfactorily solve the problem of reducing the mechanical stressesgenerated by the temperature variations to which the diffuser issubjected during operation of the burner and by temperature differencesbetween the various zones of the diffuser; nevertheless, said burnersare complex to make and are relatively expensive.

The present invention aims at providing burners of the aforementionedtype with divided diffusers that are simpler and cheaper to make.

According to the present invention a burner is provided that issuppliable with a mixture of air and fuel, comprising a burner bodyprovided with a diffuser on which openings are made for the passage andsubsequent combustion of said mixture, said diffuser being divided intoa plurality of diffuser elements that are adjacent to one another,characterised in that said diffuser elements are fixed to a support anddistribution element provided with first mechanical coupling means forcoupling with said diffuser elements and with openings for distributingsaid mixture to said diffuser elements.

Owing to the invention, the construction and assembly of the burner issignificantly simplified, in as much as a same element acts as a supportfor the diffuser elements and as a distributor of the mixture to thediffuser elements and it is therefore no longer necessary to provide adistributing element for each diffuser element. Furthermore, fixing thediffuser elements to said support and distribution element is verysimple and rapid to achieve, thus reducing considerably burner assemblytime.

Further advantages and features of the invention will be shown by thedisclosure that follows that is given merely by way of non-limitativeexample with reference to the attached drawings, in which:

FIG. 1 is a view from above of a burner according to the invention, witha substantially flat diffuser;

FIG. 2 is a view from above of a support element of the diffuser of theburner in FIG. 1, that also acts as a distributing element of themixture with which the burner is supplied;

FIG. 3 is a view from above of a diffuser element of a burner accordingto the invention;

FIGS. 4 and 5 are, respectively, a side view and a frontal view of thediffuser element of FIG. 3;

FIG. 6 is a perspective view of the diffuser element of FIG. 3;

FIG. 7 is a perspective view of a burner according to the invention,with a prismatic diffuser;

FIG. 8 is an elevation view of the burner in FIG. 7;

FIG. 9 is a plan view of the burner in FIG. 7;

FIG. 10, is a perspective view of a further embodiment of a support anddistribution element for a burner diffuser according to the invention;

FIG. 11 is a perspective view of a burner diffuser made with the supportand distribution element of FIG. 10;

FIG. 12 is a perspective view of a still further embodiment of a supportand distribution element for a burner diffuser according to theinvention;

FIG. 13 is a view from above of the support and distribution element inFIG. 12;

FIG. 14 is a perspective view of a burner diffuser made with the supportand distribution element in FIG. 12;

FIG. 15 is a view from above of the burner diffuser in FIG. 14;

FIG. 16 is a perspective view of another embodiment of a support anddistribution element for a burner diffuser according to the invention;

FIG. 17 is a perspective view of a burner diffuser made with the supportand distribution element of FIG. 16;

FIG. 18 is a perspective view of a support frame for a burner diffuseraccording to the invention;

FIGS. 19-23 illustrate details of the frame in FIG. 18.

FIG. 24 is a perspective view of a burner diffuser fitted in the frameof FIG. 18;

FIG. 25 is a partial view from above of FIG. 24;

FIG. 26 is the section XXVI-XXVI of FIG. 25;

FIG. 27 is the section XXVII-XXVII of FIG. 25;

FIG. 28 is an enlarged detail of FIG. 25;

FIG. 29 is the section XXIX-XXIX of FIG. 25;

FIG. 30 is a view from above of a further embodiment of burner diffuseraccording to the invention;

FIG. 31 is a perspective view of the diffuser in FIG. 30;

FIG. 32 is a side view of the diffuser in FIG. 30;

FIG. 33 is an enlarged detail of FIG. 32;

FIG. 34 is a view from above of a further embodiment of a support anddistribution element for a burner diffuser according to the invention;

FIG. 35 is a perspective view of the support and distribution element inFIG. 34;

FIG. 36 is the section XXXVI-XXXVI in FIG. 34;

FIG. 37 is the section XXXVII-XXXVII in FIG. 34;

FIG. 38 is a perspective view of a burner diffuser made with the supportand distribution element in FIG. 34;

FIG. 39 is a view from above of a burner diffuser according to theinvention, which illustrates an alternative arrangement of the diffuserelements on a support and distribution element;

FIG. 40 is a view like the one in FIG. 39, that illustrates a furtherarrangement of the diffuser elements on a support and distributionelement;

FIG. 41 is a view like those in FIGS. 39 and 40, which illustrates astill further arrangement of the diffuser elements on a support anddistribution element

FIG. 42 is a perspective view of a further embodiment of a support anddistribution element according to the invention;

FIG. 43 is a view according to arrow F of the support and distributionelement in FIG. 42;

FIG. 44 is a perspective view of a further embodiment of a support anddistribution element according to the invention;

FIG. 45 is a view according to arrow F1 of the support and distributionelement in FIG. 44;

FIG. 46 is a perspective view of a further embodiment of a support anddistribution element according to the invention, schematising thecoupling to a wall of a heat exchanger, or of a combustion chamber;

FIG. 47 is a perspective view of the support and distribution element inFIG. 35, schematising the coupling to a wall of a heat exchanger, or ofa combustion chamber.

FIG. 1 illustrates a first embodiment of a burner according to theinvention wherein the diffuser 1 consists of a plurality of diffuserelements 2, shown in detail in FIGS. 3 to 6, each of which has asubstantially open box shape, with an upper face 3 intended to face theoutside of the burner, two front faces 4, substantially perpendicular tothe smaller sides of the upper face 3 and two side faces 5, 6,substantially perpendicular to the larger sides of the upper face 3. Onthe upper face 3 openings 7, 8, 9 are made for the exit of the mixtureof air and fuel supplied to the burner. Said openings comprise rows ofslits 7, for example two rows parallel to one another between which aplurality of holes 8 is arranged. At regular intervals along the rows ofslits 7 and holes 8 further slits 9 can be arranged that extend over theentire width of said upper face 18. These further slits 9, in additionto acting as further openings for the passage of said mixture, enablesaid upper face 3 to absorb heat expansion without being subject toexcessive mechanical stresses generated by said expansion. From each ofthe side faces 5, 6, appendages 10 protrude that are tilted towards thecorresponding appendages 10 of the opposite side face, the function ofwhich will be explained below.

The diffuser elements 2 are fitted next to one another on a support anddistribution element 11, that may have the form of a flat quadrangularplate, as shown in FIGS. 1 and 2, but may also have a polygonal,circular oval shape and have a convex surface. In the plate 11 slits 12are made that are arranged in rows that are substantially parallel toone another and are intended to be coupled with the appendages 10 of thediffuser elements 2 to fix the elements in position. The plate 11 isfurthermore provided with groups of rows of holes 13, each group beingarranged between two rows of slits 12, in such a way as to be level witha diffuser element 2 when the diffuser elements 2 are fitted to theplate 11. The groups of rows of holes 13 distribute the mixture of airand fuel delivered to the burner to the openings 7, 8, 9 of eachdiffuser element 2, guaranteeing a distribution of the flow of mixtureto the aforementioned openings. The rows of slits 12 and the rows ofholes 13 can be arranged parallel to a pair of opposite sides of theplate 11 or tilted in relation to the sides of the plate 11. The plate11 performs both the function of support to the diffuser elements 2 andthe function of distributor of the flow of mixture, which makes theburner structure more compact and makes assembly thereof very simple, itno longer being necessary to provide a separate distributor element foreach diffuser element.

The plate 11, with the diffuser elements 2 that are fixed to it,constituting the diffuser 1 of the burner, can be fixed to a supportframe, with a shape corresponding to the shape of the plate 11, whichwill be disclosed below.

The diffuser elements 2 can be made of metal, ceramic material or of anyother material resistant to the operating temperatures of the burner.The upper face 3 of the diffuser elements 2, rather than being providedwith the openings 7, 8, 9, can be made of porous material with poredimensions sufficient to ensure the passage of the mixture of air andfuel without excessive load losses.

FIGS. 7, 8 and 9 show a second embodiment of a burner according to theinvention, in which the diffuser elements 2 are fixed to a support anddistribution element 14 with a prismatic shape, which similarly to theplate 11 disclosed previously, also performs the function of distributorof the mixture of air and fuel delivered to the burner. Each face of thesupport and distribution element 14 is provided with two parallel rowsof slits 12, intended to be coupled with the appendages of a diffuserelement 2, to fix in position the diffuser element 2 on the respectiveface of the support element 14. Between the two rows of slits 13parallel rows of holes 13 are arranged, to distribute the mixture to theopenings made on the upper face of the diffuser element 2.

The burner is completed by an upper base and by a lower base that arenot shown, in one of which a hole is made for connecting a pipesupplying the mixture of air and fuel.

The support and distribution element 14 may as an alternative have acylindrical shape, in which the diffuser elements 2 will preferably havea slightly arched shape, in such a way as to define as a whole adiffuser 1 with a substantially cylindrical shape.

In FIGS. 10 to 17 further versions of the support and distributionelement in a burner according to the invention are shown.

In FIGS. 10 and 11 a support and distribution element 14 a is shown thathas an upper face 15 in which a plurality of rows of slits 12 is madefor fixing diffuser elements 2; between pairs of rows of adjacent slits12 rows of holes 13 are made for distributing to the respective diffuserelement 2 the mixture of air and fuel supplied to the burner. Both therows of slits 12 and the rows of holes 13 are arranged parallel to apair of opposite sides of said upper face 15.

The support and distribution element 14 a furthermore has two L-shapedside faces 16, 17 connected to a pair of opposite sides of the upperface 15, to constitute two support feet for the support and distributionelement, suitable for example for facilitating the coupling with asupport frame and/or adjusting the height of the diffuser of the burnerinside a combustion chamber, by varying for example the height H of theside faces 16, 17. In the support and distribution element 14 a the rowsof slits 12 and the rows of holes 13 are arranged perpendicular to thepair of sides to which the side faces 16 and 17 are connected. In FIGS.12 to 14 another version of a support and distribution element 14 baccording to the invention is shown, which differs from the support anddistribution element 14 a inasmuch as the rows of slits 12 and the rowsof holes 13 are parallel to the pair of sides to which the side faces 16and 17 are connected. A burner according to the invention can be madewith a support and distribution element 14 a, 14 b, with the respectivediffuser elements 2 fixed thereto (FIGS. 11 and 14, 15), all fitted in asupport frame.

Alternatively, a burner according to the invention can be made with aplurality of support and distribution elements 14 a, 14 b that areplaced near one another and fitted in a containing frame, with therespective diffuser elements 2 fixed to each support and distributionelement 14 a, 14 b.

In FIGS. 16 and 17 a still further version of a support and distributionelement 14 c is shown that differs from the support and distributionelements 14 a and 14 b by the fact that it has a box structure with anL-shaped side face 16, 17, 18, 19 connected to each of the sides of theupper face 15; rows of slits 12 and holes 13 are arranged parallel to apair of opposite sides of the upper face 15 of the support anddistribution element 14 c.

The rows of slits 12 and the rows of holes 13 made in the upper face 15of the support and distribution elements 14 a, 14 b, 14 c can also bearranged tilted in relation to the sides of said upper face 15.

The upper face 15 of the support and distribution elements 14 a, 14 b,14 c, similarly to the plate 11, may be flat and quadrangular in shape,but also have a polygonal, circular, oval shape and have a convexsurface.

FIGS. 18 to 23 show an embodiment of a support and containing frame 21,with which the support and distribution elements 11, 14 a, 14 b, 14 ccan be coupled, with the relative diffuser elements 2, to assemble aburner according to the invention.

The frame 21 is a composable frame 21, consisting of two pairs of frameelements 22, 22 a; 23, 23 a that are assemblable together. Each element22, 22 a of the first pair of frame elements consists of a substantiallyrectangular flat element 24 a longitudinal edge 25 of which is foldedback into a squashed “S” shape, with an upper part 25 a having a heighta and a lower part 25 b having a height b<a.

Each element 23, 23 a of the second pair of frame elements also consistsof a flat element 26, a longitudinal edge 27 of which is folded backinto a non-squashed “S” shape, with an upper part 27 a having a height cand a lower part 27 b having a height d.

The height c of the upper part 27 a of the longitudinal edge 27 is lessthan the height a of the upper part 25 a of the longitudinal edge 25 andthe height d of the lower part 27 b of the longitudinal edge 27 isgreater than the height b of the lower part 25 b of the longitudinaledge 25.

The frame elements 22, 22 a, 23, 23 a are coupled together to form aquadrangular frame, as shown in FIG. 18, by inserting the upper part 27a of each edge 27 of the frame elements 23, 23 a inside the upper part25 a of each edge 25 of a corresponding frame element 22, 22 a, whereasthe lower part 25 b of each edge 25 of the frame elements 22, 22 a isinserted into the lower part 27 b of a corresponding frame element 23,23 a, all as shown in FIG. 19. The fixing of the frame elements 22, 22a, 23, 23 a can be achieved by crushing the elements after they havebeen coupled together and can be reinforced by welding.

FIGS. 24 to 29 illustrate the assembly of a support and distributionplate according to the invention, for example a plate of the type shownin FIGS. 1 and 2.

Two opposite edges 11 a of the plate 11 are inserted inside the upperparts 25 a of the longitudinal edges 25, folded into the shape of asquashed “S”, of the elements 23, 23 a, of the frame 21, as shown inFIGS. 26 and 27, whereas the other two opposite edges 11 b of the plate11 are inserted in upper parts 27 a of the longitudinal edges 27, foldedinto the shape of a non-squashed “S”, of the elements 22, 22 a of theframe 21, as shown in the FIG. 29.

When the frame elements are fixed together by crushing, the edges 11 a,11 b of the plate 11 remain immobilised in the respective squashed frameelements.

The plate 11 shown in FIGS. 24 to 29 has a slightly convex shape, butthe same assembly can be achieved with a flat plate 11, or with a plate14 a, 14 b, 14 c.

FIGS. 30 to 33 show another diffuser version 28, associable with a frame21 like the one shown in FIG. 18 and/or a support and distribution plate11, 14 a, 14 b, 14 c.

The diffuser 28 consists of a plurality of diffuser elements 29 arrangedparallel to one another and connected together along the longer sides byelastic-hinge connecting means 30.

The elastic-hinge connecting means 30 are used to absorb the heatexpansion generated by the temperature variations to which the diffuser28 is subjected during burner operation, thus enabling a reduction ofthe mechanical stresses due to said heat expansion and an increase inthe working life of the diffuser 28.

The diffuser 28 may be provided with appendages similar to theappendages 10 of the previously disclosed diffuser elements 2 forcoupling with a support and distribution plate 11, 14 a, 14 b, 14 c.

FIGS. 34 to 37 show a further embodiment of a support and distributionelement 31 according to the invention, which has an upper face 32 inwhich a plurality of rows of slits 12 is made for fixing diffuserelements 31; between pairs of rows of adjacent slits 12 rows of holes 13are made for distribution to the respective diffuser element 2 of themixture of air and fuel supplied to the burner. Both the rows of slits12 and the rows of holes 13 are arranged parallel to a pair of oppositesides of said upper face 15.

The support and distribution element 31 furthermore has two side faces33, 34 connected to a pair of opposite sides of the upper face 32. Theside faces 33, 34 are each provided with a recess 35, 36 that extendsover the entire length of the respective side face 33, 34. The recesses35, 36 are suitable for facilitating, for example, coupling with asupport frame and/or enabling easy coupling of the support anddistribution element 31 with a combustion chamber or a heat exchanger.

The upper face 32 of the support and distribution element 31, similarlyto the plate 11 and to the upper face 15 of the support and distributionelements 14 a, 14 b, 14 c, may be flat and quadrangular in shape but mayalso have a polygonal, circular, oval shape and have a convex surface.

The diffuser elements 2 can be assembled on the support and distributionelements 11, 14 a, 14 b, 14 c, 31, not only in configurations shown inFIGS. 1, 11, 14, 15, 17, 38, but also according to any otherconfiguration. Certain non-limitative examples of other configurationsof the diffuser elements 2 are illustrated in FIGS. 39, 40 and 41.

FIG. 39 illustrates a support and distribution element 11, on whichthree groups of diffuser elements 31 are arranged.

The diffuser elements 2 of each group are parallel to one anotherwhereas the diffuser elements 2 of the central group are oriented in adirection substantially perpendicular to the diffuser elements 2 of theother two groups.

FIG. 40 illustrates a support and distribution element 11 on which twogroups of diffuser elements 2 are arranged that are separated by a spaceS free of diffuser elements.

FIG. 41 illustrates a support and distribution element 11, on which fourgroups of diffuser elements 2 are arranged tilted in relation to thesides of the support and distribution element and delimiting a centralspace S1 free of diffuser elements 2.

The slits 12 and the holes 13 on the support and distribution elementmust be arranged in such a way as to correspond to the arrangement ofthe diffuser elements 31.

As already said, any other arrangement configuration of the diffuserelements 2 is possible, by distributing in a corresponding manner theslits 12 and the holes 13, the configuration of the diffuser elements 2thus being adaptable, for example, to the features of the heat exchangerof a boiler in which a burner according to the invention is installed.

FIGS. 42 and 43 illustrate a further version of a support anddistribution element 37, that has an upper face 38 in which a pluralityof rows of slits 12 is made for fixing diffuser elements 2; betweenpairs of adjacent rows of slits 12 rows of holes 13 are made for thedistribution to the respective diffuser element 2 of the mixture of airand fuel supplied to the burner. Both the rows of slits 12, and the rowsof holes 13 are arranged parallel to a pair of opposite sides of saidupper face 15. The support and distribution element 37 furthermore hastwo side faces 39, 40 connected to a pair of opposite sides of the upperface 38. The side faces 39, 40 are each provided with a plurality ofrecesses 41 arranged on each of said side faces 39, 40. The recesses 41are suitable for facilitating, for example, coupling with a supportframe and/or enabling easy coupling of the support and distributionelement 31 with a combustion chamber or a heat exchanger.

FIGS. 44 and 45 illustrate a further embodiment of a support anddistribution element 42 according to the invention that differs from thesupport and distribution element 37 shown in FIGS. 42 and 43 due to thefact that the side faces 39, 40 are provided with a plurality ofprotrusions 43, having the same function as the recesses 41 made on theside faces 39, 40 of the support and distribution element 37.

FIG. 46 shows a further embodiment of a support and distribution element44 according to the invention, similar to the support and distributionelement 31 shown in FIG. 35, from which it differs due to the fact thatthe side faces 33, 34 are each provided with respective protrusions 45,46 that extend along the entire length of the respective side face 33,34 and which perform the same function as the recesses 35, 36 made inthe side faces of the support and distribution element 31.

FIG. 46 furthermore schematically illustrates the fixing of the supportand distribution element 44 to a heat exchanger or to a combustionchamber. Fixing occurs by coupling one of the protrusions 45, 46 with acorresponding recess 48 made in a respective wall 47 of the heatexchanger or of the combustion chamber.

FIG. 47 illustrates the fixing of a support and distribution element 31to a heat exchanger or to a combustion chamber. In this case, fixingoccurs by means of coupling of one of the recesses 35, 36 with acorresponding protrusion 49 made in a corresponding wall 47 of the heatexchanger or of the combustion chamber.

Similarly, with reference to the versions of the support anddistribution element illustrated in FIGS. 42 to 45, fixing of thesupport and distribution element 37, 42 to a heat exchanger or to acombustion chamber occurs by coupling of the recesses 41 or protrusions43 with corresponding protrusions or recesses made on the walls of theheat exchanger or of the combustion chamber.

In the practical embodiment, the materials, the dimensions and theconstructional details may be different from those indicated but betechnically equivalent without thereby falling outside the legal scopeof the present invention.

1-48. (canceled)
 49. A Burner suppliable with a mixture of air and fuel,comprising a diffuser on which apertures are made for the passage andsubsequent combustion of said mixture, said diffuser being divided intoa plurality of diffuser elements that are adjacent to one another,wherein said diffuser elements are fixable to a support and distributionelement provided with first coupling elements for coupling with saiddiffuser elements and openings for distributing said mixture to saiddiffuser elements.
 50. The burner according to claim 49, wherein saiddiffuser elements are provided with second coupling elements suitablefor coupling with said first coupling elements.
 51. The burner accordingto claim 50, wherein said first coupling elements comprises furtheropenings made in said support and distribution element.
 52. The burneraccording to claim 51, wherein said second coupling elements comprisesappendages of said diffuser elements, suitable for coupling with saidfurther openings.
 53. The burner according to claim 51, wherein saidfurther openings are arranged in rows, said rows being arranged inpairs, the rows of each pair of rows being parallel to one another. 54.The burner according to claim 53, wherein each pair of rows of saidfurther openings is provided for coupling with the appendages of adiffuser element.
 55. The burner according to claim 51, wherein saidfurther openings have the shape of slits.
 56. The burner according toany one of claims 53, wherein said openings for distributing saidmixture are arranged between said pairs of rows of said furtheropenings.
 57. The burner according to claim 56, wherein said openingsare arranged in rows parallel to the rows of said further openings. 58.The burner according to claim 51, wherein said support and distributionelement has the shape of a quadrangular, circular, polygonal or ovalplate.
 59. The burner according to claim 58, wherein said plate is flat.60. The burner according to claim 58, wherein said plate is convex. 61.The burner according to claim 58, wherein said rows of openings and saidrows of further openings are arranged parallel to a pair of oppositesides of said plate.
 62. The burner according to claim 58, wherein saidrows of openings and said rows of further openings are arranged tiltedin relation to the sides of said plate.
 63. The burner according claim51, wherein said support and distribution element has a tubular,cylindrical or prismatic shape.
 64. The burner according to claim 51,wherein said support and distribution element comprises an upper faceand two “L”-shaped side faces, connected to a pair of opposite sides ofthe upper face, to act as two support feet.
 65. The burner according toclaim 64, wherein in said upper face a plurality of rows of said furtheropenings is made, between pairs of rows of said further openings rows ofsaid openings being made, both the rows of further openings and the rowsof openings being arranged parallel to a pair of opposite sides of saidupper face.
 66. The burner according to claim 64, wherein in said upperface a plurality of rows of said further openings is made, between pairsof rows of said further openings rows of said openings being made, boththe rows of further openings and the rows of openings being arrangedtilted in relation to sides of said upper face.
 67. The burner accordingto claim 51, wherein said support and distribution element comprises anupper face and four “L”-shaped side faces, each of which is connected toa respective side of the upper face.
 68. The burner according to claim67, wherein in said upper face a plurality of rows of said furtheropenings is made, between pairs of rows of said further openings rows ofsaid openings being made, both the rows of further openings and the rowsof openings being arranged parallel to a pair of opposite sides of saidupper face.
 69. The burner according to claim 67, wherein in said upperface a plurality of rows of said further openings is made, between pairsof rows of said further openings rows of said openings being made, boththe rows of further openings and the rows of openings being arrangedtilted in relation to sides of said upper face.
 70. The burner accordingto claim 51, wherein said support and distribution element comprises anupper face and two side faces connected to a pair of opposite sides ofthe upper face, each of said side faces being provided with connectingmeans suitable for allowing the connection of said support anddistribution element to a heat exchanger or to a combustion chamber. 71.The burner according to claim 70, wherein said connecting meanscomprises at least a recess obtained in each of said side faces.
 72. Theburner according to claim 71, wherein said at least a recesssubstantially extends over the entire length of the respective sideface.
 73. The burner according to claim 70, wherein said connectingmeans comprises at least a protrusion obtained in each of said sidefaces.
 74. The burner according to claim 73, wherein said at least aprotrusion substantially extends over the entire length of therespective side face.
 75. The burner according to claim 70, wherein insaid upper face a plurality of rows of said further openings is made,between pairs of rows of said further openings rows of said openingsbeing made, both the rows of further openings and the rows of openingsbeing arranged parallel to a pair of opposite sides of said upper face.76. The burner according to claim 70, wherein in said upper face aplurality of rows of said further openings is made, between pairs ofrows of said further openings rows of said openings being made, both therows of further openings and the rows of openings being arranged tiltedin relation to the sides of said upper face.
 77. The burner according toclaim 49, furthermore comprising a composable support and containingframe with which said support and distribution elements are couplable.78. The burner according to claim 77, wherein said frame comprises afirst pair of frame elements and a second pair of frame elements thatare assemblable together to constitute said frame.
 79. The burneraccording to claim 78, wherein each element of said first pair of frameelements consists of a flat substantially rectangular element alongitudinal edge of which is folded into a squashed “S” shape.
 80. Theburner according to claim 79, wherein said longitudinal edge comprisesan upper part and a lower part, said upper part having a height greaterthan a height of said lower part.
 81. The burner according claim 80,wherein each element of said second pair of frame elements consists of aflat substantially rectangular element a respective longitudinal edge ofwhich is folded into an “S” shape.
 82. The burner according to claim 81,wherein said respective longitudinal edge comprises an upper part and alower part, said upper part having a height lower than the height ofsaid upper part of the longitudinal edge of each frame element of saidfirst pair of frame elements, said lower part having a height greaterthan the height of said lower part of each frame element of said firstpair of frame elements.
 83. A support and containing frame for a burner,characterised in that it comprises a first pair of frame elements and asecond pair of frame elements that are assemblable together toconstitute said frame.
 84. The frame according to claim 83, wherein eachelement of said first pair of frame elements consists of a substantiallyrectangular flat element a longitudinal edge of which is folded backinto a squashed “S” shape.
 85. The frame according to claim 84, whereinsaid longitudinal edge comprises an upper part and a lower part, saidupper part having a height greater than a height of said lower part. 86.The frame according to claims 85, wherein each element of said secondpair of frame elements consists of a substantially rectangular flatelement a respective longitudinal edge of which is folded back into anon-squashed “S” shape
 87. The frame according to claim 86, wherein saidrespective longitudinal edge comprises an upper part and a lower part,said upper part having a height lower than the height of said upper partof the longitudinal edge of each frame element of said first pair offrame elements, said lower part having a height greater than the heightof said lower part of each frame element of said first pair of frameelements.
 88. A burner suppliable with a mixture of air and fuel,comprising a diffuser on which holes are made for the passage and thesubsequent combustion of said mixture, said diffuser being divided intoa plurality of diffuser elements adjacent to one another, wherein saiddiffuser elements are connected together by elastic hinge connectingelements.
 89. The burner according to claim 88, wherein said diffuser isprovided with coupling elements suitable for enabling coupling of saiddiffuser with a support and distribution element, said support anddistribution element being provided with further coupling elements forcoupling with said diffuser elements and openings for distributing saidmixture to said diffuser elements.
 90. The burner according to claim 89,wherein said further coupling elements comprises further openings madein said support and distribution element.
 91. The burner according toclaim 90, wherein said coupling elements comprises appendages of saiddiffuser elements suitable for coupling with said further openings ofsaid support and distribution element.
 92. The burner according to claim88, wherein said diffuser elements are made of metal material.
 93. Theburner according to claim 88, wherein said diffuser elements are made ofceramic material.
 94. The burner according to claim 88, wherein saiddiffuser elements are made of a material with great resistance to theburner's operating temperatures.
 95. The burner according to claim 88,wherein said diffuser elements have an upper face made of porousmaterial.
 96. The burner according to claim 88, wherein said diffuserelements are arranged on said support and distribution element accordingto any arrangement configuration.